Flow interrupter type gas safety control operated by rotary knob for pilot,on and off in any rotary position of knob



NOV. 11, 1969 R, K FMRLEY ET AL 3,477,641

FLOW INTERRUPTER TYPE GAS SAFETY CONTROL OPERATED BY ROTARY KNOB FORPILOT, ON AND OFF IN ANY ROTARY POSITION OF KNOB Filed June 23, 1967 oFF52 E- 74 76 @Si 72 Q2 M 66 B n ze 7- I/azJl l ,l Il Il 00 Je ,GO f@ @W961V l@ 5246 'l l K 44 e4 8o 40 42 1 1 f 43 32 l f/g 20* /7 20 Ix k f a 37 'l J7 j A Q/fzwwzw' United States Patent O 3,477,641 FLOW INTERRUPTERTYPE GAS SAFETY CON- TROL OPERATED BY ROTARY KNOB FOR PILOT, ON AND OFFIN ANY ROTARY POSI- TION OF KNOB Richard K. Fairley, Deerfield, Ill.,and Lourdes V. McCarty, Milwaukee, Wis., assignors to Controls Companyof America, Melrose Park, Ill., a corporation of Delaware Filed June 23,1967, Ser. No. 648,490 Int. Cl. F23n 5/06; G05d 23/12 U.S. Cl. 236-1 10Claims ABSTRACT OF DISCLOSURE The manually operated knob is rotated toturn cam surface to set the bias on and temperature to be maiutained bythe temperature responsive valves. In any rotary position of the knob itcan be pushed in (pilot position) to interrupt gas ow to the main burnerwhile allowing flow to the pilot burner for ignition purposes and theknob may be pulled out to allow the safety valve to close even thoughthe thermo-electrically energized electromagnet is energized. The knobcannot be depressed to pilot if the magnet is still energized afterhaving moved the knob to olf On, off, and pilot functions are obtainedwithout changing temperature setting.

CROSS-REFERENCES TO RELATED APPLICATIONS The means preventing movementto pilot after off actuation until the thermomagnet is de-energized isclaimed in application Ser. No. 648,489.

The snap andmodulating valve arrangement is claimed in application Ser.No. 647,766.

BACKGROUND OF INVENTION The flow interrupter type safety control is wellknown in the art but has generally required some separate means to turnoff the gas. There have, however, been some designs which can turn offthe gas. For example, Thomas United States Patent No. 2,988,098 shows anarrangement for rotating the knob to uncouple the safety valve from theelectromagnet and allow the valve to close. This patent also shows anarrangement requiring recoupling before the safety valve can be reopenedand the recoupling is possible only after the electromagnet isde-energized. This latter feature satisfies some of the newer safetyrequirements.

SUMMARY OF INVENTION The present invention combines the aforesaidfeatures of a ow interrupter operable to pilot-on-ofr' with a rotaryknob which also sets Ithe temperature to be maintained by the controland the rotary position (temperature Setting) of the knob need not bedisturbed to obtain the pilot-on-of operation. Hence a single knobcontrols all functions.

DESCRIPTION OF DRAWING The single figure in the drawing shows a verticalsection through the control with some of the parts simplilied orrendered schematically for the sake of clarity.

DESCRIPTION OF PREFERRED EMBODIMENT `The control 'housing 10 is providedwith an inlet 12 leading to chamber 14 through the cylindrical filter16. The safety valve 17 comprises a slightly dished resilient seatingmember 18 backed up by plate 20 which is slidable on stem 22 between thelimits defined by the two 3,477,641 Patented Nov. 11, 1969 ice wire snaprings 24, 26. The upper hub portion of plate 20 has a threaded sectionreceiving the cap 28. The very light spring 30 urges the safety valveupwardly to the limit imposed by the upper ring 24. A release plate 32is fixed on the stem with its outer rim turned downwardly and is urgedupwardly by the compressed spring 34. The lower end of the shaft 22carries the usual armature inside the housing 36. Also contained in thehousing is an electromagnet which is connected to a thermocouple 37heated by llame at pilot burner 39 to generate suflicient energy toenergize the electromagnet sufficiently to hold the armature to themagnet but insuiciently to attract the armature. This isa rathercustomary use of electromagnetic safety controls. If the electromagnetbecomes de-energized because the pilot flame goes out then spring 34will move release plate 32 and stem 22 upwardly `to close the safetyvalve on seat 38.

Immediately downstream of the safety valve there is a conduit 40 leadingto the pilot burner 39. Immediately downstream of this conduit there isa seat 42 against which the ow interrupter valve 44 may seat. This valveis urged downwardly by spring 46 to rest on the outwardly turned flange48 of sleeve 50 connected to plunger or shaft 52 and containing spring54 which acts against the head of pin 56 to urge the pin downwardly witha force greater than spring 30 but less than spring 34. In the positionshown the thermocouple has been energized sufficiently to hold thesafety valve open and there is flow to the pilot burner through outlet40 and the interrupter valve is held open by reason of its engagementwith the shoulder 48 on sleeve 50 which is unable to move downwardly. Inthis position it will be noted that spring 54 is slightly compressed. Ifthe electromagnet becomes deenergized spring 34 has sufficient force toovercome spring S4 acting on pin 56 to move the safety valve upwardlyand close the safety valve to thereby interrupt all ow of gas both tothe pilot 39 and the main burner 57.

1f, starting from the normal on position shown in the drawing, the knob55 is retracted, shaft 52 will be pulled outwardly which necessitatesthe movement of the spring loaded detent ball 58 until it is free todrop on the other side of the spindle portion 60 of the plunger. Th-usit would then be seated on the underside of the spindle. At this pointthe pin 56 has taken up the lost motion between the head of the pin andthe inside surface of the sleeve member 50i and has been withdrawn,whereupon the light spring 30 acting on the underside of the safetyvalve can move the safety valve 17 upwardly at least far enough for theflexible valve portion 18 to seat against seat 38 and interrupt ow. Thishaving occurred, the thermocouple will cool sufliciently to release thearmature and allow spring 34 to move the release plate 32 upwardly andcontinue the closing action on the safety valve. If, however, ratherthan waiting for the thermocouple to cool down, the user immediatelytried to reset the control by pushing down on knob 55 past the positionshown so as to rst seat the interrupter valve 44, the action would beineffective to accomplish the normal resetting action since the inwardlybiased latches 62, 62 would have moved in underneath the plate 20 of thesafety valve and would prevent any opening of the safety valve. It willbe appreciated that latches 62, 62 are selfbiased inwardly and if plate32 is down (retained) and plate 20 is up (seating valve 18) the latchescan move between plates 32 and 20 until plate 32 is released to spreadthe latches. Therefore, the user would of necessity have to wait untilthe thermocouple became cool to de-energize the electromagnet and allowthe release plate 32 to move upwardly and spread the latches 62, 62 tothe position in which they can no longer block downward movement of thesafety valve. This, then, prevents the 3 user from undertaking to lightthe burner under conditions which could allow full ow of raw gas to anunlighted burner.

Under normal operating conditions the resetting action occurs bydepressing the knob 55 which will again move the detent 5S out of theway and the interrupter valve 44 is seated rst and during this period oftime the spring 54 is compressed until it virtually goes solid, that is,acts as a solid member. Continued downward motion of the knob and itsplunger 52 will now act to move the safety valve off its seat and movethe armature to the electromagnet. This now allows flow only to thepilot burner 39 since flow past the interrupter valve is prevented.After ignition has been effected release of the knob allows spring 64 toreturn the knob to the normal position shown and the parts will havebeen restored to the normal operating condition shown.

The present control is unique in that the knob 55 can be rotated toadjust the temperature. Thus it will be noted that keyed to the shaft 52there is a collar 66 having a cam track 68 formed therein and the leftend 70 of lever 72 contacts and is positioned by the cam track. Thelever 72 pivots about pin 74 and the right end is connected by means ofadjusting screw 76 to actuating pin 78. The lower end of the actuatingpin acts on a combined snap and modulating valve arrangement. For thepurpose of understanding the present invention it is only necessary toknow that as the pin 78 moves down the rst action which occurs is toopen snap valve 80 and thereafter continued motion will operate to openthe modulating valve 82. When the snap valve 80 is opened flow passesthrough the pressure regulator, designated by the box 84, and thencethrough the now open snap valve to conduit 86 which leads to the mainoutlet 88. The amount of gas which can flow through the bypass conduit86 is adequate for the low re condition. Then as the pin moves down morethe valve 82 can open to add additional fuel to that supply until themaximum flow rate is reached. The pin 78 and lever 72 are actuated bybellows 90 acting on lever 92 which is pivoted on pin 94 and urged byspring 96 to follow the motion of the bellows pin 100. The lever 92carries the pivot pin 74 and the spring 102 compressed between the twolevers causes lever 72, to follow the motion of pin 74 as modified bythe position of cam 68 acting on the end 70` of lever 72. It will beunderstood that the bellows is connected by capillary tubing 104 to asuitable bulb 106 placed in the heated medium so that the pressurewithin the bulb and bellows assembly varies in accordance withtemperature.

From the foregoing it will be appreciated that the present controlprovides a single knob 55 which can be used to actuate a ow interrupterassembly both to the normal operation of resetting and the on positionbut can also cause the safety valve to close even though the pilot isstill energizing the electromagnet. Furthermore, all of these functionscan occur in any rotary position of the knob. The knob can set thetemperature control and the setting need not be altered during operationof the knob to reset or oi What is claimed is:

1. A gas control including a housing having an inlet, a pilot outlet anda main outlet,

resettable safety valve means requiring a linear resetting action andoperative when reset to respond to a control condition to allow flow toboth outlets and to prevent such flow when in its off position,

reset means for imparting the linear reset action to the resettablemeans and including interrupter valve means for preventing ilow to themain outlet during resetting,

a manually operable knob having a normal axial position and mounted foraxial movement and connected to the reset means for operating the resetmeans upon being depressed,

said knob also being rotatable about its axis,

control means including temperature responsive valve means the responsetemperature of which is affected by the rotary position of the knob,

'a spring biasing the knob to its normal axial position,

`said knob being mounted for withdrawal from its noranal position andoperative upon such withdrawal to effect movement of the resettablesafety valve means to the off position.

2. A gas control including a housing having an inlet,

a pilot outlet anda main outlet,

a safety valve operative when closed to prevent flow to both outlets andwhen open to allow such flow,

an armature,

an electromagnet energized in response to a control condition to retainthe armature in attracted position,

said safety valve being connected to the armature and held open when thearmature is in attracted position,

reset means for moving the armature to attracted position and openingthe valve,

said reset means including an interruptor valve preventing ow to themain outlet during resetting,

said pilot outlet being supplied from the space between said valves,

a manually operable knob mounted on the housing for rotary and axialmovement and connected to the reset means for actuating the reset meansupon axial movement of the knob from its normal position to ya resetposition,

and a thermostat adjusted by rotary movement of the knob,

said knob being axially movable in any of its rotary positions to eifectresetting without affecting the adjustment of the thermostat.

3. A control according to claim 2 in which the safety valve is connectedfor limited motion relative to the armature with la spring actingtherebetween tending to close the safety valve notwithstanding theattraction of the armature to the electromagnet,

said reset means including means for yieldably holding the safety valveto the armature with a force greater than the force of the spring actingbetween the safety valve and the armature,

said knob being movable from its normal axial position in a directionopposite the reset position to an off position in which the yieldableholding means is ineffective and the safety valve can close.

4. A gas control of the type having a housing lprovided with an inlet, amain outlet and a pilot outlet with a safety valve controlling flow toboth outlets and held open by an electromagnet which requires resettingfollowing de-energization of the electromagnet, and resetting meansincluding a plunger which is depressed from its normal position to resetthe safety valve while an interrupter valve carried by the plungerblocks flow to the main outlet, the improvement comprising,

thermostatic control means,

adjusting means carried by the plunger yand operative upon rotation ofthe plunger to adjust the thermostatic control means,

means responsive to withdrawal of the plunger from its normal positionto close the safety valve regardless of the state of energiz'ation ofthe electromagnet,

said plunger being actuatable to reset or close the safety valve in anyrotary position so the adjustment of the thermostatic means isunaifected.

5. A -gas control according to claim 4 in which the electromagnetarmature is connected to the safety valve with a limited motionconnection and a spring biases the safety valve to closed position evenwhen the armature is held by the electromagnet,

said plunger including a pin acting on the safety valve when the plungeris in its normtal or reset position and withdrawn from the safety valvewhen the plunger is withdrawn from its normal position,

a spring biasing the pin from the plunger with a force `greater than thespring biasing the safety valve closed,

said yarmature being biased to the valve closed by a spring exerting aforce greater than the force of the spring biasing the pin from theplunger.

6. A control according to claim 5 including a detent acting on theplunger t0 hold it in either its normal or its withdrawn position,

and a spring acting on the plunger to move it from the reset position tothe normal position upon removal of the actuating force applied to theplunger during resetting.

7. A control according to claim 6 including valve means downstream ofthe nterrupter valve for controlling flow to the main outlet,

said thermostatic means includin-g a motor device responsive to thetemperature of the heated medium and lever means connected to the motordevice and the valve means.

8. A control according to claim 7 in which the adjusting means comprisesa cam carried by the plunger for rotation therewith but allowing 'axialmovement of the plunger without movement of the cam, said cam acting onthe lever means.

9. A gas control of the type having a housing provided with an inlet, amain outlet and a pilot outlet with a safety valve controlling flow toboth outlets land held open by an electromagnet which requires resettingfollowing de-energization of the electromagnet, and resetting means including a plunger which is moved axially from its normal position to areset position to reset the safety valve while an interrupter valvecarried by the plunger blocks flow to the main outlet, the improvementcomprising,

mounting the plunger for axial movement to an 01T position,

means responsive to movement of the plunger to the oi position to closethe safety `valve regardless of the state of energiz-ation of theelectromagnet.

10. A gas control according to claim 9 in which the plunger is rotatablymounted and the plunger is axially movable to elect its functions in anyrotary position of the plunger.

References Cited UNITED STATES PATENTS 3,129,884 4/1964 Baatrup.

2,557,927 6/ 1951 Abrams et al.

2,628,677 2/ 1953 Strobel.

2,690,873 10/ 1954 Vaughn 236-21 2,7017,5 17 5/ 1955 Strobel.

2,911,152 11/1959 Weber et a1.

EDWARD I. MICHAEL, Primary Examiner U.S. Cl. XR. 137-66; 431-75

